Breaker-to-Breaker Runs
4 runs
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Breaker-to-breaker runs measure continuous operation between refueling outages using a cycle-adjusted threshold (90% of cycle length minus RFO duration). An active streak means the unit has been running continuously since the last refueling with no trips to 0% power.
D.C. Cook 2 has logged 4 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 497 days, and its runs average 479 days.
497
Best Run (days)
U2C27 (2022-11-12) → U2C28 (2024-03-23)
★ Double breaker-to-breaker
U2C26 → U2C27 → U2C28
All Runs
| 2022-11-12 |
2024-03-23 |
497 days |
U2C27 → U2C28 |
| 2021-07-08 |
2022-10-01 |
450 days |
U2C26 → U2C27 |
| 2010-12-05 |
2012-03-21 |
472 days |
U2C19 → U2C20 |
| 2006-05-07 |
2007-09-15 |
496 days |
U2C16 → U2C17 |
About This Site
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Written by NukeWorker from public records: facts that do not change. Operator, status and capacity come from the live data elsewhere on this page. Sources: Wikipedia: Donald C. Cook Nuclear Plant.
Donald C. Cook Nuclear Plant is a two-unit nuclear station in Lake Township, Berrien County, Michigan, near Bridgman, on a 650-acre site on the shore of Lake Michigan, about 11 miles south of St. Joseph.
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Construction began in March 1969. Both units are Westinghouse pressurized water reactors with ice condenser containment. Unit 1 was first connected to the grid on February 10, 1975, and Unit 2 on March 22, 1978. In 1976 two workers died from argon gas in a recirculation pit during welding. In September 1997 both units shut down for about three years after NRC inspections raised doubts about the emergency core cooling systems. On September 20, 2008, broken turbine blades led to a fire in the Unit 1 generator.
Facility Statistics
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Key performance and lifecycle metrics calculated from NRC operational data. Includes operating age, construction timeline, capacity factor, efficiency, generation totals, and reliability records.
D.C. Cook 2 has operated for about 48.4 years and averaged a 83.8% lifetime capacity factor, generating roughly 229.6 TWh of electricity. Its longest unbroken run reached 527 days.
Lifecycle & Tenure
Operating Age: 48.4 Yrs
Build Time: 9.3 Yrs
Lic. Remaining: 11.1 Yrs
Production & Power
Lifetime CF: 83.8%
Efficiency: 33.7%
Generated: 229.6 TWh
Reliability & Outages
Record Run: 527 Days
Refuelings: 17
Avg Startup: 5.6 Days
Ownership & Construction
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The utility or company that owns and operates the facility, the architect-engineer responsible for plant design, and the primary construction contractor. Click names to view all facilities by that entity on the map.
Ownership, operation and management history
No change of owner, operator or management company on record. Our history starts in 1999.
AEP
American Electric Power Company, Inc.
NasdaqGS
$126.53
▼ -0.24 (-0.19%)
Previous Close
126.77
Day's Range
124.23 – 127.16
52-Week Range
112.54 – 140.58
Volume
3,669,255
Operational Excellence Score Subscribers
D.C. Cook 2 is rated 0 to 100 on how well it actually runs, scored against every other operating reactor in the US fleet from its own operating record. Subscribers see the score, the three sub-scores behind it, and each of the seven measured inputs.
- This unit's composite score and fleet rank
- Reliability, Efficiency and Discipline sub-scores
- All seven measured inputs, with fleet percentiles
- Rank against comparable units, not just the fleet
- Three-year, five-year and lifetime windows
- Five-year trend, and every other operating US reactor
Scram History
14 events since 2011
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Automatic and manual reactor scram (emergency shutdown) events reported to the NRC since 2011. Includes event dates, trip type, and average recovery time. Click the title to view the full fleet scram dashboard.
D.C. Cook 2 has recorded 14 reactor scrams, or emergency shutdowns, since 2011 (5 automatic, 9 manual). On average the unit was back to full power about 10.4 days after each trip.
Recent Events
| 2026-01-18 |
Auto |
AUTOMATIC REACTOR TRIP The following information was provide... |
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| 2024-05-15 |
Manual |
UNIT 2 MANUAL REACTOR TRIP The following information was pro... |
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| 2024-03-22 |
Auto |
REACTOR TRIP DUE TO MAIN TURBINE TRIP The following informat... |
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| 2022-11-10 |
Auto |
AUTOMATIC REACTOR TRIP AND AUXILIARY FEEDWATER SYSTEM ACTUAT... |
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| 2021-06-22 |
Manual |
EN Revision Imported Date: 7/22/2021 EN Revision Text: MANUA... |
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| 2020-10-12 |
Auto |
AUTOMATIC REACTOR TRIP "At 0026 [EDT] on October 12, 2020, D... |
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| 2020-09-04 |
Manual |
MANUAL REACTOR TRIP AND AUTOMATIC SAFETY INJECTION "On Septe... |
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| 2019-07-21 |
Manual |
MANUAL REACTOR TRIP DUE NON-ESSENTIAL SERVICE WATER SYSTEM D... |
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+6 more events
Technical Specs
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Reactor design specifications including type (PWR/BWR), containment design, nuclear steam supply system manufacturer, thermal and electrical power ratings, and current operational status.
Turbine Supplier:
BROWN BOVERI & CIE IAEA
Thermal Power:
3468 MWt
Net Capacity:
1168 MWe
Gross Capacity:
1,231 MWe IAEA
Design Capacity:
1,100 MWe IAEA
Efficiency:
33.7%
Lifetime Output:
336.6 TWh through 2025 IAEA
Licensing
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NRC licensing history including docket number, license type and number, construction permit date, operating license issuance, commercial operation date, license renewal, and expiration date.
Docket #:
05000316
License #:
DPR-74
License Type:
OL-FP
Const. Permit:
1969-03-25
Construction Start:
1969-03-25 IAEA
Operating Lic:
1977-12-23
First Criticality:
1978-03-10 IAEA
Grid Connection:
1978-03-22 IAEA
Commercial Op:
1978-07-01
License Renewed:
2005-08-30
License Exp:
2037-12-23
Market & Region
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EIA market and grid-region classifications: NERC reliability region, U.S. Census region, balancing authority responsible for grid operations, and whether the unit operates as a rate-regulated utility or a competitive merchant generator. Hover any value for the full name.
NERC Region:
RFC
— Reliability First Corporation
Census Region:
ENC
— East North Central
Balancing Authority:
PJM
— PJM Interconnection (ISO/RTO)
Market Structure:
Regulated
— Rate-regulated utility (cost-of-service pricing)